It seems astonishing that in the 21st century decisions on health care can still be made without a solid grounding in research evidence. This is true even in clinical research, whether for simple or complex interventions, where systematic reviews time and time again conclude that the evidence base is inadequate. It is even more true in the areas of health policy and health systems, where quality research is hampered further by a lack of shared definitions, a lack of consensus on guiding principles, poor capacity (especially in low-resource regions), and methodological challenges.